BUG make sure to remove any blank versions

[beckermr]

cc @isuruf

I think a recent change in the pinnings file triggered this edge case. It turns out the bot also does not care about None or undefined.

[codecov]

Codecov Report

Merging #1329 (8238fc0) into master (7899aab) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #1329      +/-   ##
==========================================
- Coverage   57.66%   57.65%   -0.01%     
==========================================
  Files          66       66              
  Lines        6569     6570       +1     
==========================================
  Hits         3788     3788              
- Misses       2781     2782       +1     

Impacted Files	Coverage Δ
conda_forge_tick/auto_tick.py	0.00% <0.00%> (ø)

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